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OC Astronomy is Orange County’s answer to the night’s sky, Astronomy News, Astronomy Toolkit, OC Star Spots, Local Astronomy Groups, Star Blog, and more!"

10/30/2026

Haunting the Cepheus Flare

Spooky shapes seem to haunt this dusty expanse, drifting through the night in the royal constellation Cepheus. Of course, the shapes are cosmic dust clouds visible in dimly reflected starlight. Far from your own neighborhood, they lurk above the plane of the Milky Way at the edge of the Cepheus Flare molecular cloud complex some 1,200 light-years away. Over 2 light-years across and brighter than most of the other ghostly apparitions, vdB 141 or Sh2-136 is also known as the Ghost Nebula. It lies at lower right in the starry field of view. Inside the Ghost Nebula are reddish telltale signs of dense cores collapsing in the early stages of star formation. With the eerie hue of interstellar dust reflecting bluish light from hot young stars of NGC 7023, the Iris Nebula stands out against the dark just left of center. In the broad telescopic frame, these fertile interstellar dust fields stretch almost six full moons across the sky.

Credit & Copyright: Mirko Tondinelli
Authors & editors: Jerry Bonnell, Cecilia Chirenti, Robert Nemiroff, Keighley Rockcliffe
A service of: ASD at NASA / GSFC,
NASA Science Activation & Michigan Tech. U.

10/28/2026

Andromeda Before Photoshop

What does the Andromeda galaxy really look like? The featured before image shows how our Milky Way Galaxy's closest major galactic neighbor really appears in a long exposure through Earth's busy skies and with a digital camera that introduces normal imperfections. The picture is a stack of 223 images, each a 300 second exposure, taken from a garden observatory in Portugal during 2019. Obvious image deficiencies include bright parallel airplane trails, long and continuous satellite trails, short cosmic ray streaks, and bad pixels. In the after image, these imperfections were actually not removed with Photoshop specifically, but rather greatly reduced with a series of computer software packages that included Astro Pixel Processor, DeepSkyStacker, and PixInsight. All of this work was done not to deceive you with a digital fantasy that has little to do with the real likeness of the Andromeda galaxy (M31), but to minimize Earthly artifacts that have nothing to do with the distant galaxy and so better recreate what M31 really does look like.

Credit & Copyright: Kees Scherer
Authors & editors: Robert Nemiroff, Jerry Bonnell, Cecilia Chirenti, Keighley Rockcliffe
A service of: ASD at NASA / GSFC,
NASA Science Activation & Michigan Tech. U.

10/26/2026

Dark Matter in a Simulated Universe

Is our universe haunted? It might look that way on this dark matter map. The gravity of unseen dark matter is the leading explanation for why galaxies rotate so fast, why galaxies orbit clusters so fast, why gravitational lenses so strongly deflect light, and how visible matter is distributed. The featured image from the American Museum of Natural History's Hayden Planetarium Space Show, Dark Universe, highlights one example of how pervasive dark matter might haunt our universe. In this frame from a detailed computer simulation, complex filaments of dark matter, shown in black, are strewn about the universe like spider webs, while the relatively rare clumps of familiar baryonic matter are colored orange. These simulations are good statistical matches to astronomical observations. In what is perhaps a scarier turn of events, dark matter -- although quite strange and in an unknown form -- is no longer thought to be the strangest source of gravity in the universe. That honor now falls to dark energy, a more uniform source of repulsive gravity that seems to now dominate the expansion of the entire universe.

Credit & Copyright: Tom Abel & Ralf Kaehler (KIPAC , SLAC), AMNH
Authors & editors: Robert Nemiroff, Jerry Bonnell, Cecilia Chirenti, Keighley Rockcliffe
A service of: ASD at NASA / GSFC,
NASA Science Activation & Michigan Tech. U.

10/23/2026

Stickney Crater

Stickney Crater, the largest crater on the martian moon Phobos, is named for Chloe Angeline Stickney Hall, mathematician and wife of astronomer Asaph Hall. Asaph Hall discovered both the Red Planet's moons in 1877. Over 9 kilometers across, Stickney is nearly half the diameter of Phobos itself, so large that the impact that blasted out the crater likely came close to shattering the tiny moon. This enhanced-color image of Stickney and surroundings was recorded by the HiRISE camera onboard the Mars Reconnaissance Orbiter as it passed within some six thousand kilometers of Phobos in March of 2008. Even though the surface gravity of asteroid-like Phobos is less than 1/1000th Earth's gravity, streaks suggest loose material slid down inside the crater walls over time. Light bluish regions near the crater's rim could indicate a relatively freshly exposed surface. The origin of the curious grooves along the surface is mysterious but may be related to tidal stresses experienced by close-orbiting Phobos or the crater-forming impact itself.

Credit: HiRISE, MRO, LPL (U. Arizona), NASA
Authors & editors: Jerry Bonnell, Cecilia Chirenti, Robert Nemiroff, Keighley Rockcliffe
A service of: ASD at NASA / GSFC,
NASA Science Activation & Michigan Tech. U.

10/21/2026

New Ghosts Revealed in Cassiopeia

Jinkies, look at all those ghosts! It took 100 hours of observation and a special oxygen filter for today’s image to capture three faint nebulas hidden in the Cassiopeia constellation. IC 59 and IC 63, the original Ghosts of Cassiopeia, haunt the region near multi-star system γ Cassiopeia. Energetic light from γ Cassiopeia causes the hydrogen gas in IC 59 and 63 to glow red. Their dust reflects and scatters some blue-ish white starlight. Newly discovered Objects 1, 2, and 3 appear as blue phantoms, revealing the presence of ionized oxygen. But ionized by what? Like at the bow of a speeding boat, γ Cassiopeia may be piling up material as the system moves through interstellar gas and dust. It follows that Object 3 may be the compressed and heated oxygen of that bow shock. Object 1 could be a planetary nebula if a central white dwarf is identified. The origins of these astronomical apparitions remain a mystery to be solved.

Tomorrow's picture: it's not easy being green

Credit & Copyright: Louis Leroux-Géré, Thibault Rouillée, Vincent Martin, Cédric de Decker (Starfront Observatories)
Authors & editors: Keighley Rockcliffe, Robert Nemiroff, Jerry Bonnell, Cecilia Chirenti
A service of: ASD at NASA / GSFC,
NASA Science Activation & Michigan Tech. U.

10/19/2026

Treble Clef: Unusual X-ray Hot Radio Source

What is Treble Clef? This unusual radio structure extends over 2 million light-years and resembles a common musical symbol -- but has its visible light hidden by our own Milky Way Galaxy. Examined in 2004, the nature of VLSS J0318.9+5755, dubbed Treble Clef, remained unknown. Recent observations by the Chandra X-ray Observatory and eROSITA, however, have led to the hypothesis that the Treble Clef central cloud of charged particles was originally expelled by a supermassive black hole at the center of a galaxy. After the radio emission from those particles faded, they may have been reinvigorated by a shock wave from the collision of two clusters of galaxies. The featured composite image shows radio emission in red, while recently discovered X-rays are shown in blue. Unusual objects like Treble Clef give humanity unexpected clues about how whole clusters of galaxies interact as well as the general evolution of our universe.

Credit:
X-ray: NASA/CXC/INAF-IRA/A. Botteon et al.;
Infrared: UKIDSS-GPS;
Radio: ASTRONLOFAR;
Image processing: NASA/CXC/SAO/N. Wolk
Authors & editors: Robert Nemiroff, Jerry Bonnell, Cecilia Chirenti, Keighley Rockcliffe

10/16/2026

The Large Magellanic Cloud

Have you ever seen another galaxy with your own eyes? The featured image shows the Large Magellanic Cloud (LMC), one of the closest neighbors of our Milky Way. If you are anywhere south of latitude 20° N (but the further south, the better), you can see it with the unaided eye if you go to a dark sky location, away from big cities and light polution. It is a dwarf irregular galaxy about 163,000 light-years away, and a member of our Local Group of galaxies. Despite being small, with a total mass approximately equivalent to 10% - 20% of the mass of the Milky Way, the LMC is very actively forming stars. This is likely due in part to the gravitational push and pull of tides caused by the Milky Way on the LMC. Some astronomers have predicted that it will collide with the Milky Way in in about 2 billion years.

Credit: Monica Mesa
Authors & editors: Robert Nemiroff, Jerry Bonnell, Keighley Rockcliffe, Cecilia Chirenti

10/14/2026

Vaporizing Meteor Photobombs the Lacerta Nebula

What's happening to this meteor? This bright meteor streak appeared and disappeared quickly during a long exposure of the Great Lacerta Nebula, seen faintly in red toward the center of the image. The meteoroid, likely a small pebble, creates its glow partly by heating and exciting surrounding air in Earth's atmosphere, but itself vaporizes and leaves wind-blown gas and dust with colors that give clues to its composition. The featured image was captured last month from Death Valley Observatories in Nevada, USA. This month, though, is particularly good for seeing meteors. Presently there are three meteor showers ongoing, although they are currently competing for visibility with the glow of a bright gibbous Moon. The most active of these showers, the Perseids, will be busiest in about 10 days -- after the Moon has dimmed considerably. This year, the Perseids peak nearly coincides with not only a new Moon, but, from some locations, one that totally eclipses the Sun.

Credit & Copyright: Tom Burnett
Authors & editors: Robert Nemiroff, Jerry Bonnell, Cecilia Chirenti, Keighley Rockcliffe

10/12/2026

Perseids over a Little Planet

It looks like a view from the Little Prince's planet. The featured image is a throwback to the 2024 Perseid meteor shower, surrounded in this projection by the Bieszczady Mountains in Poland. Visible in the sky is the arch of the Milky Way, along with several nebulas in red and over a hundred meteors pointing to the radiant. The Perseids are easily visible and quite popular in the Northern Hemisphere summer. (Watching meteor showers in the winter is less convenient for a good reason). This year they are expected to offer an even more dazzling spectacle than usual, because the peak coincides with a new moon. The 2026 Perseid meteor shower will peak tonight with as many as 50-100 meteors per hour, when the Earth's path crosses through debris left behind by Comet Swift-Tuttle. Typically, the best times for seeing the meteors are between midnight and pre-dawn. You won't need binoculars to see the meteors, but a lawn chair and a dark sky location help.

Credit & Copyright: Marcin Rosadziński
Authors & editors: Cecilia Chirenti, Jerry Bonnell, Robert Nemiroff, Keighley Rockcliffe

10/09/2026

JWST Images The Lion's Head Nebula
Explanation: Are we looking at the future of our Sun? The James Webb Space Telescope captured today’s composite image of the Lion’s Head Nebula (NGC 2392) with its NIRCam and MIRI instruments. The Lion’s Head Nebula is the remnant of a Sun-like star. This star was unable to sustain the nuclear fusion in its core needed to remain stable. It began to shed layers of gas and dust into space, forming this planetary nebula. A hot stellar core, called a white dwarf, is left behind within the lion’s nose. Do not boop this nose! Intense radiation from the white dwarf is ionizing the gas as it expands, creating the irregular bubble that makes up the lion’s face. Dust clumps that have survived the white dwarf’s radiation and a cloud of ionized gas make up the lion’s mane. This new and more detailed view of the nebula will help humanity learn more about how the gas and dust interact with each other and the white dwarf radiation.

Credit Image: NASA, ESA, CSA, STScI; Image Processing: Alyssa Pagan (STScI)
Authors & editors: Keighley Rockcliffe, Robert Nemiroff, Jerry Bonnell, Cecilia Chirenti

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